Sorry about the delay on my riddle. Takes me longer to check my threads on this connection. Especially on someone else's computer.
Anyway, the thing which is fast, red, orange, and hits you like a freight train is a Tackle Me Elmo.
Now, of course, you've given me the idea of deliberately posting riddles and never answering them. Especially the uncomplicated, pun-dependent kind that get under peoples' scalps and make them sit awake for hours.
Hell, I don't even have to know the answer, so I can get really devious.
*cackle*